Method And Apparatus For Controlling Energy Expanding Of Sensor Network Nodes

ABSTRACT

Present invention is to provide a method and apparatus for controlling energy expanding of sensor network nodes, wherein the method comprises steps of: acquiring energy information, said energy information being indicative of an energy status of a node in the network; and adjusting at least one data transmission parameter accordingly based on the energy information. With present invention, on the premise that the communication capacity and power energy of sensor nodes are limited in a wireless sensor network, it is capable of efficiently utilize the network resource, save the power consumption of sensor node, and prolong the whole life of sensor network.

FIELD OF THE INVENTION

This invention is related to a wireless sensor network, in particular,to a method and apparatus for controlling energy expanding of wirelesssensor network nodes.

BACKGROUND OF THE INVENTION

There are some limitations to the sensor network. Firstly, thecommunication capacity of sensor network is very limited; thecommunication bandwidth of sensors in sensor network is narrow and oftenvaried, and the coverage range of communication is only several tensmeters to hundreds meters. If the data transmission exceeds theavailable bandwidth, a high lost-packet rate will be caused.

Secondly, the power energy of sensors is very limited; a lot of energyis required in the information sensing of sensor network, data processand communication, and if the node power supply of sensor network underBatteries-Supply can not be replaced, the energy consumption it causedwill directly affect the lifecycle of whole sensor network.

Cluster head data fusion is means of reducing node energy consumption byreducing network traffic. In accordance with this means, sensor networkusually includes a plurality of node cluster, and each node clusterincludes a central node, and a sensor network is divided into aplurality of sensor sub network, so it can avoid that data communicationbottleneck of transferring original data directly from each sensor nodeto sensor network base station.

Furthermore, the operation mode based on wake-up when required betweencoverage node (i.e. cluster head node) and sensor node in Zigbee networkcan also partly solve the problem of energy supply in the sensornetwork.

However, a plurality of sensor nodes is included in the sensor network,and data process and communication status of each sensor node isdifferent each other, the corresponding energy consumption status isdifferent each other. Therefore, on the premise that the communicationcapacity and power energy of sensor nodes are limited in a wirelesssensor network, the problems of how to efficiently utilize the networkresource to save the power consumption of sensor node and prolong thewhole life of sensor network still need to be solved.

SUMMARY OF THE INVENTION

Present invention is to provide a method and apparatus for controllingenergy expanding of sensor network nodes, which are capable ofefficiently utilize the network resource to save the power consumptionof sensor node, and prolong the whole life of sensor network.

In accordance with a method for controlling energy expanding of anetwork of present invention, comprising steps of: acquiring an energyinformation, said energy information being indicative of an energystatus of a node in the network, and; adjusting at least one datatransmission parameter accordingly based on the energy information.

In accordance with an apparatus for controlling energy expanding of anetwork of present invention, comprising: an acquiring device foracquiring an energy information, said energy information beingindicative of an energy status of a node in the network, and; anadjusting device, for adjusting at least one data transmission parameteraccordingly based on the energy information.

In accordance with a product of computer program for controlling energyexpanding of a network of present invention, comprising: code foracquiring an energy information, said energy information beingindicative of the energy status of a node in the network, and; code foradjusting at least one data transmission parameter accordingly based onthe energy information.

In accordance with a network of present invention, comprising: aplurality of nodes, and; a network controller connected with saidplurality nodes; wherein said network controller comprising: anacquiring device for acquiring an energy information, said energyinformation being indicative of an energy status of a node in thenetwork, and; an adjusting device, for adjusting at least one datatransmission parameter accordingly based on the energy information.

In summary, on the premise that the communication capacity and powerenergy of sensor nodes are limited in a wireless sensor network, theapparatus and method of present invention can adjust data transmissionparameter of the nodes accordingly based on the energy information ofthe nodes, save the power consumption of sensor node, and prolong thelife of sensor network, in order to more efficiently utilize the networkresource.

In the following, other objects and achievements of present inventionwill be apparent through the description of present invention and claimswith reference to the figures, and prevent invention will be fullyunderstood.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustrative view of a sensor network configuration inaccordance with an embodiment of present invention.

FIG. 2 is an illustrative view of a sensor network configuration inaccordance with another embodiment of present invention.

FIG. 3 is an illustrative view of functional configuration of networkcontroller in a sensor network in accordance with an embodiment ofpresent invention.

FIG. 4 is method flow chart of controlling energy expanding of sensornetwork nodes in accordance with an embodiment of present invention.

FIG. 5 is an illustrative view of method of controlling energy expandingof sensor network nodes in accordance with an embodiment of presentinvention.

In all of above figures, same references denote the same, similar orcorresponding characters or functions.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following, the preferred embodiments of present invention will bedescribed in details with reference to the accompany figures.

In accordance with one embodiment of present invention, presentinvention will be described in details with respect to a method andapparatus for controlling energy expanding of sensor nodes in a wirelesssensor network. It will be understood by those skilled in the art thatpresent invention could be modified and applied in other types ofnetwork, such as Bluetooth network or Wireless Local Area Network(WLAN), on the basis of without departing the scope of content ofpresent invention.

In a wireless sensor network, in order to ensure a successful datatransmission, a node transmits data to a receiving node, and thereceiving node will send back feedback information after successfulreceives the data, so as to acknowledge the successful datatransmission. If the node that sends data does not receive any feedbackinformation about successful data transmission in a retransmissiontimeout, the data will be re-sent. If the node that sends data doesstill not receive any feedback information about successful datatransmission after re-sending, the data will be re-sent for many times,until the data are transmitted successfully. Alternatively, if it isstill not successful after a certain times of re-sending, the datatransmission will be given up.

FIG. 1 is an illustrative view of a sensor network configuration inaccordance with an embodiment of present invention. This sensor networkincludes a sensor network controller 110, a plurality of wireless sensornodes 120, and a plurality of wired sensor nodes 130.

The sensors 120 and 130 are connected to the sensor network controller110 via wired or wireless connection, wherein the sensor networkcontroller 110 being used to collect data, the function thereof beingsimilar to a base station in a wireless communication network or arouter in a wired communication network, or a combination of them. Thewired communication between each sensor 120 and 130 and the sensornetwork controller 110 is via Local Area Network (LAN) or via dedicatedcommunication line, and the wireless communication may adopt theWireless Local Area Network (WLAN) or Bluetooth standard.

The respective sensor nodes 120, 130 transmit the information ofdetecting result and so on to the sensor network controller 110, forexample, the wired transmission shown in solid line in the figures. Atthe same time, the sensor network controller 110 may also send thecontrol signals to the respective sensors 120, 130, for example, thewired transmission shown in dashed line in the figures; which will beoptimized. The optimization process includes determining whether theinformation will be transmitted through a certain sensor, adjusting thesampling rate of a certain sensor, or determining whether the data of acertain sensor will be encrypted, and so on. It could be viewed fromFIG. 1 that the sensor network controller 110 is a convergent point ofall the detected data, and to analysis and process the detected data,and then educe a process center of the detected results, which is also acontrol center of optimizing the network.

FIG. 2 is an illustrative view of a sensor network configuration inaccordance with another embodiment of present invention. In thisembodiment, a plurality of sensors 120 and 130 are connected to the datacollector 210 via wired or wireless connection, constituting a sensornetwork 220. Distinct sensor networks 220, 230 and 240 are connectedwith the sensor network controller 250 via their respective datacollectors. The sensor network controller 250 collects sensor data fromthe respective sensor networks 220, 230 and 240, as well as sends acontrol command to the respective sensor networks 220, 230 and 240.Above various optimization processes are performed to the respectivesensors 120 and 130 in the network are op220, 230 and 240 by the datacollector, such as 210.

As shown in FIG. 3, it is an illustrative view of functionalconfiguration of network controller in a sensor network in accordancewith an embodiment of present invention.

The sensor network controller 300 includes a energy informationacquiring device 312 and a adjusting device 320, wherein the energyinformation acquiring device 312 is used to acquire energy information,the energy information being indicative of the energy status of one nodein the network. For example, the energy information may be indicative ofthe power supply status of a sensor node, for instance, the power statusof a node may be classified into three levels, i.e. high, middle, andlow, which are expressed by the values of 3, 2, and 1 respectively.

The energy information is monitored by the power monitor device (notshown in the figures) on the nodes in the network, and then transferredto the energy information acquiring device 312.

The adjusting device 320 is used to adjust at least one datatransmission parameter of the node accordingly based on the energyinformation. Wherein the data transmission parameter may be theretransmission timeout and/or retransmission times, the retransmissiontimeout being the timeout in which the node that sends data will resendthe data if it does not receive any feedback information aboutsuccessful data transmission; the retransmission times being times atwhich the node that sends data will resend the data if it does notreceive any feedback information about successful data transmission.

In accordance with an embodiment of present invention, the sensornetwork controller 300 may further include an available bandwidthacquiring device 314, for acquiring the status of available bandwidthwhen a node is transmitting data. The status of available bandwidth maybe monitored by the network monitor device (not shown in the figures),and then transferred to the available bandwidth acquiring device 314.

The adjusting device 320 includes a timeout adjusting device 322, foradjusting the retransmission timeout of a sensor node based on theenergy information acquired by the acquiring device. The more sufficientpower supply the sensor node has, the shorter timeout is retransmittingthe data to the objective sensor node adjusted to, and otherwise, thelonger timeout is retransmitting the data adjusted to. In this way, thepower consumption of the sensor node could be saved.

The adjusting device 320 includes a retransmission times adjustingdevice 324, for adjusting the times of retransmitting data after thedata transmission failed, based on the energy information acquired bythe acquiring device. The more sufficient power supply the sensor nodehas, the more times are retransmitting the data to the objective sensornode adjusted to, and otherwise, the less times are retransmitting thedata adjusted to. In this way, the power consumption of the sensor nodecould be saved.

The sensor network controller 300 further includes a transmission device330, for the sensor nodes to send and receive data, and communicate withother sensor nodes in the sensor network. For example, the transmissiondevice 330 may be a signal transmitter/receiver under the protocol ofZigbee/Bluetooth network.

In present embodiment, acquiring the power of the network controller 300can be achieved by bandwidth acquiring, and the functions of adjustingthe retransmission timeout and adjusting the retransmission times can beperformed by various nodes in a sensor network, as long as these variousnodes can communicate each other.

It should be understood that the all/part of functions of the sensornetwork controller 300 disclosed in FIG. 3 according to an embodiment ofpresent invention, can also be achieved by appropriately programmedcomputer, the computer being loaded with a computer program forcontrolling energy expanding of sensor network nodes. The computerprogram includes: code for acquiring energy information, said energyinformation being indicative of the energy status of a node in thenetwork, and; code for adjusting at least one data transmissionparameter accordingly based on the energy information.

Above such a computer program can be stored in a storage media.

These parts of above computer program code can be provided to aprocessor to generate a machine, so that the code executed on theprocessor creates a device that can achieve above functions.

As shown in FIG. 4, it is method flow chart of optimizing the wirelesssensor network in accordance with an embodiment of present invention.

At first, at step S410, the data transmission parameters of respectivesensor nodes in the sensor network are initialized. During theinitializing communication process, convergent node broadcastsconnection signaling actively, and after a data frame and a MAC (MediaAccess Control) command frame are successful received and verified at asensor node, an acknowledge frame is returned to the convergent node.Next, the sensor node is brought into a sleep operation mode. Next, theconvergent node and the sensor node are master-slave exchanged, and theconvergent node module is brought into a mode operation status, andwaiting for a response for connecting request signaling; and the sensornode is operated in the master mode, and waiting for wake-up whenrequired or launches a connecting request in other ways.

After initialization, two initialized data transmission parameters canbe obtained: a retransmission timeout and a retransmission times.

At step S420, the sensor node starts to transmit the data to anothersensor node.

At step S430, it is to determine whether an acknowledge informationabout a successful data transmission fed-back from another sensor nodeis received in an initialized retransmission timeout. If an acknowledgeinformation is received in the retransmission timeout, the whole processwill end immediately.

If an acknowledge information is not received by the sensor node in theinitialized timeout, at step S335, it is to determine that whether thetotal trial times of data retransmission (i.e. the initializedretransmission times or adjusted retransmission times) have beenreached. If the total trial times of data retransmission have beenreached, the whole process will end immediately.

If it is determined that the total trial times of data retransmissionhave not been reached, at step S340, the sensor node firstly acquiresits current energy status information, and may acquires currentavailable bandwidth information in the sensor network.

At step S450, according to the acquired energy status information and/orcurrent available bandwidth information, the retransmission timeout andretransmission times are adjusted accordingly.

The more sufficient power supply the sensor node has, the shortertimeout is retransmitting the data to the objective sensor node adjustedto, and otherwise, the longer timeout is retransmitting the dataadjusted to. In this way, the power consumption of the sensor node couldbe saved. The more sufficient power supply the sensor node has, the moretimes are retransmitting the data to the objective sensor node adjustedto, and otherwise, the less times are retransmitting the data adjustedto. In this way, the power consumption of the sensor node could besaved.

For the same reason, the more sufficient available bandwidth the sensornode has, the shorter timeout is retransmitting the data to theobjective sensor node adjusted to, and otherwise, the longer timeout isretransmitting the data adjusted to. The specific adjustment is shown inthe FIG. 5.

At step S460, according to the adjusted data transmission parameters,i.e. retransmission timeout and retransmission times, the data isretransmitted.

At step S470, it is to determine whether an acknowledge informationabout a successful data transmission fed-back from another sensor nodeis received in the adjusted retransmission timeout. If an acknowledgeinformation is received in the initialized timeout, the whole processwill end immediately. Otherwise, jump to step S440, its current energystatus information is acquired again, and current available bandwidthinformation in the sensor network is acquired, and according to theenergy status information and current available bandwidth information,the retransmission timeout and retransmission times are adjusted, untilthe data transmission is successful, or the retransmission times havebeen reached then the transmission is given up.

It could be understood that the frequency of adjusting the datatransmission data (step S450) might be adjusted according to the actualnetwork status. For example, it is to adjust once after three times ofdata transmission failure, or to adjust once in every certain period,such as 30 minutes.

FIG. 5 is an illustrative view of method of controlling energy expandingof sensor network nodes in accordance with an embodiment of presentinvention.

As shown in the figure, wherein T is indicative of interval between twodata transmissions of a sensor node; t1, t2 and t3 are indicative of thetime in which the sensor node transmits a data for many timesrespectively; b is indicative of the network available bandwidth, andbH, bM and bL are indicative of a higher available bandwidth, a middleavailable bandwidth and a lower available bandwidth respectively; pS isindicative of the power supply status of the sensor node, for example,the power status of a node may be classified into three levels, i.e.high, middle, and low, which are expressed by the power information 1,2, and 3 respectively.

Firstly, at stage 1, during the period t1, the sensor node transmits adata to an objective sensor node, and the current available bandwidth isbH, and the power supply status of the sensor node is p1, then if duringthe period T/(n*bH*p1) the sensor node does not receive an acknowledgeinformation about a successful data receipt from the objective sensornode, go to stage 2, and the data is retransmitted to the objectivesensor node. Wherein n is an adjust coefficient, for example, n may beset to equal to 20˜30 according to the actual power supply status of thesensor node.

Next, at state 2, during the period t2, the sensor node retransmits thesame data to an objective sensor node, at the same time, according tothe updated information, it is known that the current availablebandwidth is bM, and the power supply status of the sensor node is p2,and then the retransmission timeout is adjusted to: T/(n*bM*p2).

According to the adjusted timeout, if at the timet1+t2+T/(n*bH*p1)+T/(n*bM*p2), the sensor node does not receive anacknowledge information about a successful data receipt from theobjective sensor node, go to stage 3, and the data is retransmitted tothe objective sensor node.

Next, at state 3, during the period t3, the sensor node retransmits thesame data to an objective sensor node again, at the same time, accordingto the updated information, it is known that the current availablebandwidth is bL, and the power supply status of the sensor node is p3,and then the retransmission timeout is adjusted to: T/(n*bL*p3).

According to the adjusted timeout, if at the timet1+t2+t3+T/(n*bH*p1)+T/(n*bM*p2)+T/(n*bL*p3), the sensor node does notreceive an acknowledge information about a successful data receipt fromthe objective sensor node, the data is continued to be retransmitted tothe objective sensor node, until the data transmission is successful, orretransmission times have been reached then the transmission is givenup.

According to an embodiment of present invention, the times at which thedata is retransmitted to the objective sensor node can be adjustedaccordingly based on the power supply status of the sensor node. Themore sufficient power supply the sensor node has, the more is the totaltrial times to retransmit the data to the objective sensor nodeadjusted, and otherwise, the less is the (total trial) times toretransmit the data adjusted. In this way, the power consumption of thesensor node could be saved.

For example, the power status pS of a sensor node may be classified intothree levels, i.e. high, middle, and low, which are expressed by thevalue 1, 2, and 3 respectively, and then the total trial times toretransmit the data R could be calculated from R=m/pS. Wherein m is apositive integer coefficient, for example, it can be set to m—8, andthen if the power status of the sensor node pS=2, the times toretransmit the data R equals to 4 times.

It should be understood by those skilled in the art that, the method andapparatus disclosed in present invention can be modified withoutdeparting the content of present invention. Therefore, the protect scopeof present invention should be limited by the content of appendedclaims.

1. A method for controlling energy expanding of a network of presentinvention, comprising steps of: (a) acquiring an energy information,said energy information being indicative of an energy status of a nodein the network, and; (b) adjusting at least one data transmissionparameter accordingly based on the energy information.
 2. The method asclaimed in claim 1, wherein said data transmission parameter is thetimeout in which said node starts to retransmit the data after the datatransmission fails.
 3. The method as claimed in claim 1, wherein saiddata transmission parameter is the times at which said node starts toretransmit the data after the data transmission fails.
 4. The method asclaimed in claim 1, further including a step of: acquiring a bandwidthinformation, said bandwidth information is used to be indicative of theavailable bandwidth status of the node; wherein the step (b) includes astep of: based on the energy information and the bandwidth information,at least one data transmission parameter of the node is adjustedaccordingly.
 5. An apparatus for controlling energy expanding of anetwork of present invention, comprising: an acquiring device foracquiring an energy information, said energy information beingindicative of an energy status of a node in the network, and; anadjusting device, for adjusting at least one data transmission parameteraccordingly based on the energy information.
 6. The apparatus as claimedin claim 5, wherein said data transmission parameter is the timeout inwhich said node starts to retransmit the data after the datatransmission fails.
 7. The apparatus as claimed in claim 5, wherein saiddata transmission parameter is the times at which said node starts toretransmit the data after the data transmission fails.
 8. The apparatusas claimed in claim 5, further including: an bandwidth informationacquiring device for acquiring a bandwidth information, said bandwidthinformation is used to be indicative of the available bandwidth statusof the node; wherein the adjusting device is used to adjust at least onedata transmission parameter of the node accordingly based on the energyinformation and the bandwidth information.
 9. A product of computerprogram for controlling energy expanding of a network of presentinvention, comprising: code for acquiring an energy information, saidenergy information being indicative of the energy status of a node inthe network, and; code for adjusting at least one data transmissionparameter accordingly based on the energy information.
 10. A network,comprising: a plurality of nodes; and a network controller connectedwith said plurality nodes; wherein said network controller comprising:an acquiring device for acquiring an energy information, said energyinformation being indicative of an energy status of a node in thenetwork; and an adjusting device, for adjusting at least one datatransmission parameter accordingly based on the energy information.